DE 10 2014 019 724 A1 describes a method for the production of structural elements from a functional element and a fibre-plastic composite hollow profile in which local heating of the fibre-plastic composite hollow profile in the area of the undercut of a contour-defining element is carried out by optional selection of the sequence of insertion of the contour-defining element and insertion of a semi-finished structural element.
US 2012/0189403 A1 concerns a tapped insert to be produced by insert moulding that comprises a shank, at the axial ends of which flanges are provided that delimit two heads located opposite each other.
Means for axially blocking the insert in rotation after insert moulding and means for axially blocking the insert in translation after insert moulding are arranged on the outer side of the shank. The shank has at least one fusible area of greater axial deformability that is arranged between the axial threaded section and one of the axial end faces. The fusible area is configured such that an axial pressing force exerted on the axial end faces of the threaded insert presses said area into a relatively small axial longitudinal dimension without causing deformation of the axial threaded section.
WO 2009/077026 A1 describes a method for the production of a composite component from a hollow profile and an injection-moulded element, wherein the injection-moulded element is moulded onto the profile such that the profile is captively surrounded in the longitudinal direction, and wherein at least one positive-locking element is configured on the profile and is engaged in injection moulding application in that the positive-locking element lying between the ends of the profile is moulded in or out in a circumferential direction and a longitudinal direction.
The drawbacks of the solution presented in WO 2009/077026 A1 are the extremely complex and expensive methods involved on the one hand and the severely restricted design possibilities of the mechanical connections between the injection-moulded plastic component and the profile due to process-related considerations on the other.
According to WO 2009/077026 A1, an internal high-pressure forming method is first used in a combination tool before an injection moulding method is used to apply the injection-moulded element. Because of the successive combination of these two methods, first internal pressure and then injection moulding, in the same tool, this limits the minimum dimension of the wall thickness of the profile, which prevents reduction in weight in the sense of modern lightweight construction. Moreover, there are restrictions in the configuration of the connection site between the two components that finally result in a sharp reduction in the shear resistance and shear rigidity of the connection of the injection-moulded component to the profile. As the connection in WO 2009/077026 A1 is based on a positive-locking connection between the two components, said connection can be carried out only by circumferential moulding of the profile in the form of a ring—referred to in WO 2009/077026 A1 as a peripheral blade. The width of such a peripheral blade, however, is limited, and can only be a few millimetres, as this could otherwise result during the internal high-pressure forming process in undesirably high deformations of the profile wall and even to rupturing of the profile wall. According to WO 2009/077026 A1, an increase in the connection rigidity or connection strength of the profile and the injection-moulded component can therefore be achieved only by an arrangement of a plurality of such peripheral blades along the profile. In this case, a minimum distance of several millimetres must be maintained between two peripheral blades. This distance is generated in the tool by means of cores. If the width of these cores is too small, however, there is a risk of core failure and rupture of the profile, because during internal high pressure forming of the tube, the tube wall is both radially expanded and axially shifted on the cavity and the profile must therefore be supported over the largest possible area. According to WO 2009/077026 A1, only an average amount of at most 50% can be moulded onto a profile area X of 100%.
The object of the present invention was therefore to provide a method for the production of composite components in which a tolerance-sensitive, thin-walled hollow profile base element is introduced with sufficient clearance and free of resistance into an injection moulding or pressing tool, and in which nevertheless sealing of at least one cavity is achieved for a plastic melt to be applied to the hollow profile base element, and optionally its distribution around the hollow profile base element, with the applied plastic component also being connected to the exterior of the hollow profile base element without having its entire external shape deformed, thus producing an axial positive-locking composite component that is mechanically more rigid and more resistant to stress than those of the prior art.
Thin-walled within the meaning of the present invention preferably indicates a ratio of the diameter of a hollow profile to be used according to the invention to the wall thickness thereof in the range of 5:1 to 300:1.
Clearance within the meaning of the present invention means that the minimum dimension of the injection moulding or pressing tool cavity viewed perpendicular to the closing direction of the tool is always greater than, or in the borderline case equal to, the tolerance-sensitive external dimension of the hollow profile base element cross-section—likewise viewed perpendicular to the closing direction of the tools.
In addition, composite components to be produced according to the invention should not show the above-mentioned drawbacks in production or drawbacks in their resistance and rigidity properties, and thus in their energy absorption properties, and should allow a high degree of functional integration in the sense of system or module formation while allowing economical production.